Repetitive Transcranial Magnetic Stimulation (rTMS) for the Treatment of Apathy in Parkinson's Disease

In patients randomized to receive left prefrontal rTMS, each treatment will consist of 2000 stimuli (50 - 8-second trains of 40 stimuli at 5 Hz). We will administer rTMS trains every 30 seconds for 25 minutes. Stimulus intensity for the first and second trains will be 80 and 90% of MEP threshold, respectively.

Patients randomized to receive sham rTMS will undergo the same procedure for identifying stimulus location used in patients receiving real rTMS. Simulated rTMS will be administered using Magstim Placebo 70 mm figure-of-8 shaped coils which produce discharge noise and vibration similar to a real 70 mm coil without stimulating the cerebral cortex. However, in addition to obvious coil discharge noise, rTMS also causes electrical stimulation of the scalp. We will simulate this experience by attaching surface electrodes underneath the sham coil and in contact with the scalp.